U.S. patent number 8,207,637 [Application Number 12/576,661] was granted by the patent office on 2012-06-26 for system and apparatus for interconnecting an array of power generating assemblies.
This patent grant is currently assigned to SolarBridge Technologies, Inc.. Invention is credited to Robert S. Balog, Trishan Esram, Jeremiah Noel Foley, Marco A. Marroquin, Thomas Paul Parker, Stephen P. Wurmlinger.
United States Patent |
8,207,637 |
Marroquin , et al. |
June 26, 2012 |
System and apparatus for interconnecting an array of power
generating assemblies
Abstract
A system and apparatus for interconnecting an array of power
generating assemblies includes a cable assembly having a plurality
of continuous conductors and a plurality of cable connectors
electrically coupled to the continuous conductors. The continuous
conductors are configured to receive inverter AC power generated by
inverters and deliver the combined AC power to an AC grid or other
power sink. The cable connectors are configured to mate with
corresponding connectors of the inventers to deliver the AC power
to the continuous conductors.
Inventors: |
Marroquin; Marco A. (Austin,
TX), Parker; Thomas Paul (Dallas, TX), Wurmlinger;
Stephen P. (Scurry, TX), Balog; Robert S. (College
Station, TX), Esram; Trishan (Urbana, IL), Foley;
Jeremiah Noel (Austin, TX) |
Assignee: |
SolarBridge Technologies, Inc.
(Austin, TX)
|
Family
ID: |
43854268 |
Appl.
No.: |
12/576,661 |
Filed: |
October 9, 2009 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
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US 20110084556 A1 |
Apr 14, 2011 |
|
Current U.S.
Class: |
307/147; 307/84;
307/43; 307/82; 439/121 |
Current CPC
Class: |
H01L
31/02021 (20130101); H02J 3/383 (20130101); H02J
3/381 (20130101); Y02E 10/56 (20130101); H02J
2300/24 (20200101) |
Current International
Class: |
H01R
25/00 (20060101); H01R 4/00 (20060101); H02J
3/38 (20060101); H01R 3/00 (20060101) |
Field of
Search: |
;307/43,82,84,147
;439/121 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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rev. 06, 1 page, 2009. cited by other.
|
Primary Examiner: Amrany; Adi
Attorney, Agent or Firm: Barnes & Thornburg LLP
Claims
The invention claimed is:
1. A system for delivering power to an AC grid, the system
comprising: a first inverter having a first inverter connector and
being configured to deliver inverter AC power via the first
inverter connector; a second inverter having a second inverter
connector and being configured to deliver inverter AC power via the
second inverter connector; and a cable assembly configured to
receive power from the first and second inverters, the cable
assembly comprising: a first end for delivering the combined power
from the first inverter and the second inverter; a first cable
connector located at a distal end of the cable assembly opposite
the first end, the first cable connector separably mated with the
first inverter connector to receive the inverter AC power from the
first inverter, the first cable connector separable from the first
inverter connector to disconnect the first inverter from the cable
assembly, a plurality of continuous conductors electrically
connected to the first end of the cable assembly and the first
cable connector, and a second cable connector electrically coupled
to the plurality of continuous conductors via associated tap
connections between the first end of the cable assembly and the
first cable connector such that the continuous conductors are
unbroken at the tap connections, the second cable connector
separably mated with the second inverter connector to receive the
inverter AC power from the second inverter and deliver the inverter
AC power from the second inverter to the plurality of continuous
conductors, the second cable connector separable from the second
inverter connector to disconnect the second inverter from the cable
assembly.
2. The system of claim 1, wherein each of the first and second
inverters comprises an inverter cable for delivering the AC power
to the respective first and second inverter connector, the inverter
cable extending from a housing of the corresponding first and
second inverter to the respective first and second inverter
connector.
3. The system of claim 2, wherein each inverter cable comprises a
plurality of cable conductors for carrying the inverter AC power,
the plurality of cable conductors having a current-carrying
capacity less than a current-carrying capacity of the continuous
conductors.
4. The system of claim 1, wherein the cable assembly further
comprises a protective circuit element.
5. The system of claim 4, wherein the protective circuit element is
adapted to carry inverter AC power between the first cable
connector and one of the plurality of continuous conductors.
6. The system of claim 4, wherein the protective circuit element is
electrically coupled to a first continuous conductor of the
plurality of continuous conductors and a second continuous
conductor of the plurality of continuous conductors.
7. The system of claim 1, further comprising a replaceable series
element connected between the first inverter connector and the
first cable connector.
8. The system of claim 7, wherein the replaceable series element
includes a protective circuit element.
9. The system of claim 8, wherein the protective circuit element is
electrically coupled to a first continuous conductor of the
plurality of continuous conductors and a second continuous
conductor of the plurality of continuous conductors.
10. The system of claim 7, wherein the replaceable series element
is configured to carry inverter AC power between the first inverter
connector and the first cable connector.
11. The system of claim 1, further comprising a photovoltaic
module, the first inverter being electrically coupled to the
photovoltaic module to receive input power therefrom.
12. The system of claim 1, wherein the plurality of continuous
conductors comprises three continuous conductors.
13. The system of claim 1, wherein the plurality of continuous
conductors comprises an earth ground continuous conductor.
14. A cable assembly for delivering power from one or more power
generation sources to an AC grid, the cable assembly comprising: a
first end to deliver the combined power from the one or more power
generation source to the AC grid; a first cable connector located
at a distal end of the cable assembly opposite the first end, the
first cable connector configured to plug with and unplug from a
corresponding inverter connector of a first one of the power
generation sources; a plurality of continuous conductors
electrically connected to the first end and the first cable
connector and extending therebetween; a plurality of inline second
cable connectors electrically coupled to each of the plurality of
continuous conductors via associated tap connections between the
first end and the first cable connector such that the continuous
conductors are unbroken at the tap connections, each of the inline
second cable connectors configured to plug with and unplug from a
corresponding inverter connector of a corresponding one of the
power generation sources; and a replaceable series element adapted
to carry AC power between the first one of the power generation
source and the first cable connector.
15. The cable assembly of claim 14, wherein the replaceable series
element is connected between the inverter connector of the first
one of the power generation sources and the first cable
connector.
16. The cable assembly of claim 15, wherein the replaceable series
element comprises a protective circuit element.
17. The cable assembly of claim 16, wherein the replaceable series
element is configured to carry source AC power between the source
connector and the cable connector.
18. The cable assembly of claim 16, wherein the protective circuit
element is electrically coupled to a first continuous conductor of
the plurality of continuous conductors and a second continuous
conductor of the plurality of continuous conductors.
19. The system of claim 14, wherein the plurality of continuous
conductors comprises four continuous conductors.
20. A system for delivering AC power to a power sink, the system
comprising: a plurality of inverters, each inverter comprising an
inverter connector for delivering power from the inverter, and a
cable assembly comprising: (i) a first end for delivering the
combined power from the plurality of inverters to the power sink,
(ii) a first cable connector located at a distal end of the cable
assembly opposite the first end, the first cable connector
configured to selectively mate with and disconnect from the
inverter connector of a first inverter of the plurality of
inverters, (iii) a plurality of continuous conductors electrically
connected to the first end of the cable assembly and the first
cable connector, and (iv) a plurality of second cable connectors,
each second cable connector electrically coupled to the plurality
of continuous conductors via associated tap connections such that
the continuous conductors are unbroken from the first end to the
first cable connector and configured to selectively mate with and
disconnect from an inverter connector of a corresponding inverter
of the plurality of inverters, each of the second cable connectors
being wired in parallel with each other such that none of the
plurality of inverters is daisy-chained with another inverter when
the plurality of inverters is connected to the cable assembly.
Description
TECHNICAL FIELD
The present disclosure relates, generally, to a system and
apparatus for delivering power from an array of power generating
devices to a power sink and, more particularly, to an apparatus for
delivering power from an array of DC-AC inverters to an AC
grid.
BACKGROUND
Some power delivery systems comprise an array of power generation
subassemblies whose combined output power is delivered to a power
sink (a "power sink" being any device or apparatus that receives
power from a power source). One example of such a system is a
distributed photovoltaic power system in which each one of a
plurality of solar panels is provided with a DC-AC inverter
("inverter") that delivers power to an AC utility grid. Delivering
the combined power from all of the inverters to the AC grid
requires a suitable interconnection scheme. High operating
efficiency, low cost, and reliable operation over long periods of
time (e.g., twenty five years) may be highly valued features in
such systems.
A typical way of interconnecting an array of photovoltaic inverters
is illustrated in FIG. 1. As shown in FIG. 1, a distributed
photovoltaic system 100 includes a plurality of photovoltaic panels
102 and associated inverters 104a-104d. Power from the photovoltaic
panels 102 is delivered to the inverters 104a-104d by PV
interconnects 106. Each inverter 104 may include a power input
cable 108 and a power output cable 110. The power input cables 108
are terminated in input connectors 112 and the power output cables
110 are terminated in output connectors 114 that mate with the
input connectors 112. Each power input connector 112 of each
inverter 104 is connected to a power output connector 114 of an
adjacent inverter 104 to form mated connectors 116 that may carry
power between inverters.
A simplified schematic of the system 100 shown in FIG. 1 for
delivering power from inverters 104a-104d to a split-phase AC grid
(e.g., a 240VAC grid comprising two 120VAC "hot" wires 130, 132 and
a neutral wire 134) is shown in FIG. 2. As illustrated in FIG. 2,
each inverter 104 includes inverter circuitry 140 that receives DC
power from an associated photovoltaic panel 102 and delivers AC
power by means of two internal "hot" wires 130a, 132a and an
internal neutral wire 134a. When the input connectors 112 and
output connectors 114 of the inverters 104a-104d are coupled
together to form mated connectors 116, as shown in FIGS. 1 and 3,
the input cables 108 and output cables 110 are "daisy chained"
(i.e., the cables are connected in series) to form a split-phase
power bus 150 that receives power from each of the inverters 104
and carries the combined power to the AC grid 152 (inverters having
cables that are connected in this way are referred to herein as
"series-connected inverters"). An interface cable 119, connected to
the output cable 110 of inverter 104a, delivers the split-phase bus
150 into junction box 120. The junction box 120 may be an
electrical panel that connects to the AC grid or, as illustrated in
FIGS. 1 and 2, it may provide a connection point between the wires
of the split-phase bus 150 and the wiring 124 that connects to the
AC grid 152 at a downstream panel (not shown).
Inverter circuitry 140 typically includes fuses and other
protective devices, such as surge-protection devices, to protect
the system 100 and components of the system 100 from transient
electrical events and faults and to prevent failure of the entire
system in the event of a failure in a single system subassembly
(e.g., one of the inverters 104). One way to incorporate fuses and
protective devices into a series-connected inverter 104 is
illustrated in FIG. 3. As shown in FIG. 3, the inverter circuitry
140 includes a fuse 146 in series with each hot wire 130a, 132a and
surge protection devices 154a, 154b, 154c (e.g., a metal-oxide
varistor ("MOV")) connected between each pair of wires 130a, 132a,
134a.
Regulatory and safety requirements may also require that each
inverter 140 be connected to earth ground. One way to provide an
earth ground to each inverter 140, illustrated in FIGS. 1 and 2, is
to provide a ground wire 122 that is connected (e.g., by means of a
screw) to each series-connected inverter.
SUMMARY
According to one aspect, a system for delivering power to an AC
grid includes a first inverter, a second inverter, and a cable
assembly. The first inverter may include a first inverter connector
and the second inverter may include a second inverter connector.
The first inverter may be configured to deliver inverter AC power
via the first inverter connector and the second inverter may be
configured to deliver inverter AC power via the second inverter
connector. The cable assembly may be configured to receive power
from the first and second inverters. The cable assembly may include
a plurality of continuous conductors, a first cable connector, and
a second cable connector. The plurality of continuous conductors
may be configured to receive the inverter AC power delivered by the
first and second inverters and deliver the combined power to the AC
grid. The first cable connector may be electrically coupled to the
plurality of continuous conductors and configured to mate with the
first inverter connector to deliver the inverter AC power from the
first inverter to the plurality of continuous conductors.
Similarly, the second cable connector may be electrically coupled
to the plurality of continuous conductors and configured to mate
with the second inverter connector to deliver the inverter AC power
from the second inverter to the plurality of continuous
conductors.
In some embodiments, of the first and second inverters may include
an inverter cable for delivering the AC power to the respective
first and second inverter connector. Each inverter cable may
include a plurality of cable conductors for carrying the inverter
AC power. The plurality of cable conductors may have a
current-carrying capacity less than a current-carrying capacity of
the continuous conductors.
The cable assembly may include a protective circuit element. The
protective circuit element may be adapted to carry inverter AC
power between the first cable connector and one of the plurality of
continuous conductors. In some embodiments, the protective circuit
element may be electrically coupled to a first continuous conductor
of the plurality of continuous conductors and a second continuous
conductor of the plurality of continuous conductors. In some
embodiments, the protective circuit element may be embodied as a
fuse. In other embodiments, the protective circuit element may be
embodied as a surge protection device. For example, the surge
protection device may be a metal-oxide varistor.
In some embodiments, the system may further include a replaceable
series element connected between the first inverter connector and
the first cable connector. The replaceable series element may
include a protective circuit element. The replaceable series
element may be configured to carry inverter AC power between the
first inverter connector and the first cable connector. In some
embodiments, the protective circuit element may be electrically
coupled to a first continuous conductor of the plurality of
continuous conductors and a second continuous conductor of the
plurality of continuous conductors. The protective circuit element
may be embodied as a fuse. Alternatively, the protective circuit
element may be embodied as a surge protection device such as, for
example, a metal-oxide varistor.
In some embodiments, the system may further include a photovoltaic
module. In such embodiments, the first inverter may be electrically
coupled to the photovoltaic module to receive input power
therefrom. Additionally, the plurality of continuous conductors may
include three or four continuous conductors. Further, in some
embodiments, the plurality of continuous conductors may include an
earth ground continuous conductor.
According to another aspect, a cable assembly for delivering power
from one or more power generation sources to an AC grid may include
a plurality of continuous conductors, a first cable connector, a
second cable connector, and a replaceable series element. The
continuous conductors may be configured to receive power from the
power generation sources and delivering the power to the AC grid.
The first cable connector may be electrically coupled to the
plurality of continuous conductors and configured to couple with a
first power generation source to receive source AC power therefrom.
Similarly, the second cable connector may be electrically coupled
to the plurality of continuous conductors and configured to couple
with a second power generation source to receive source AC power
therefrom. The replaceable series element may be adapted to carry
AC power between the first power generation source and the first
cable connector.
In some embodiments, the first power generation source may include
a source connector and the replaceable series element may be
connected between the source connector and the first cable
connector. In such embodiments, the replaceable series element may
include a protective circuit element. The replaceable series
element may be configured to carry source AC power between the
source connector and the cable connector. Additionally, the
protective circuit element may be electrically coupled to a first
continuous conductor of the plurality of continuous conductors and
a second continuous conductor of the plurality of continuous
conductors.
The protective circuit element may be embodied as a fuse.
Alternatively, the protective circuit element may be embodied as a
surge protection device such as, for example, a metal-oxide
varistor. Additionally, in some embodiments, the system may further
include a photovoltaic module. In such embodiments, the first
inverter may be electrically coupled to the photovoltaic module to
receive input power therefrom. Additionally, the plurality of
continuous conductors may include three or four continuous
conductors. Further, in some embodiments, the plurality of
continuous conductors may include an earth ground continuous
conductor.
According to a further aspect, a system for delivering AC power to
a power sink may include a plurality of inverters and a cable
assembly. Each inverter may include a inverter connector for
delivering power from the inverter. The cable assembly may include
a plurality of separable cable connectors and a first cable end.
Each separable cable connector may be configured to separably mate
with one of the inverter connectors to receive AC power from the
corresponding inverter. The first cable end may be configured to
deliver the combined power received from the plurality of inventors
to the power sink. Additionally, the cable assembly may be
configured such that the AC power delivered by each inverter to the
power sink passes through only one separable cable connector
between the respective inverter and the first cable end.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a distributed photovoltaic power
system;
FIG. 2 is a simplified schematic of the system of FIG. 1;
FIG. 3 is a schematic of protective circuitry for an inverter of
the system of FIG. 1;
FIG. 4 is a perspective view of a distributed photovoltaic power
system according to the present disclosure;
FIG. 5 is a simplified schematic of one embodiment of the system of
FIG. 4;
FIG. 6 is a simplified schematic of one embodiment of protective
circuitry of the system of FIG. 4;
FIG. 7 is a perspective view of one embodiment of a portion of the
system of FIG. 4 including a series replaceable element;
FIG. 8 is a simplified schematic of one embodiment of protective
circuitry of the series replaceable element of FIG. 7;
FIG. 9 is a simplified schematic of a portion of the system 100 of
FIG. 4 including one embodiment of an earth grounding
interconnection;
FIG. 10 is a simplified schematic of a portion of the system 100 of
FIG. 4, including one embodiment of a series replaceable element
and an earth grounding interconnection;
FIGS. 11a-11c are simplified illustrations of various embodiments
of tapped connections; and
FIG. 12 is an illustration of one embodiment of an overmolded
tapped connection.
DETAILED DESCRIPTION
While the concepts of the present disclosure are susceptible to
various modifications and alternative forms, specific exemplary
embodiments thereof have been shown by way of example in the
drawings and will herein be described in detail. It should be
understood, however, that there is no intent to limit the concepts
of the present disclosure to the particular forms disclosed, but on
the contrary, the intention is to cover all modifications,
equivalents, and alternatives falling within the spirit and scope
of the invention as defined by the appended claims.
References in the specification to "one embodiment", "an
embodiment", "an example embodiment", etc., indicate that the
embodiment described may include a particular feature, structure,
or characteristic, but every embodiment may not necessarily include
the particular feature, structure, or characteristic. Moreover,
such phrases are not necessarily referring to the same embodiment.
Further, when a particular feature, structure, or characteristic is
described in connection with an embodiment, it is submitted that it
is within the knowledge of one skilled in the art to effect such
feature, structure, or characteristic in connection with other
embodiments whether or not explicitly described.
Referring now to FIGS. 4 and 5, in one embodiment, a distributed
photovoltaic system 200 includes a plurality of photovoltaic panels
202 and associated inverters 204a-204d. Although the illustrative
system 200 includes four photovoltaic panels 202 and associated
inverters 204, it should be appreciated that system 200 may include
two, three, or more panels 202 and associated inverters 204 in
other embodiments. Power from the photovoltaic panels 202 is
delivered to the inverters 204 by PV interconnects 206. Each
inverter 204a-204d includes a power delivery cable 210 terminated
in a power delivery connector 212. For ease of comparison with the
system 100 of FIGS. 1 and 2, the system 200 of FIGS. 4 and 5 is
configured to deliver power from inverters 204a-204d to a
split-phase AC grid (e.g. a 240VAC grid comprising two 120VAC "hot"
wires and a neutral wire). However, in other embodiments, the
system 200 may be configured to deliver power to other power
sinks.
The system 200 includes a power delivery cable assembly 220 to
which each of the inverters 204 is electrically coupled via a
corresponding power delivery cable 210. The power delivery cable
assembly 220 delivers the power received from each of the inverters
204 to an the AC grid via an AC junction box 240, which may be an
electrical panel that connects to the AC grid or, as illustrated in
FIGS. 4 and 5, may provide a connection point between bus
conductors 230, 232, 234 and wiring 224 that connects to an AC grid
at a downstream panel (not shown).
The power delivery cable assembly 220 includes a power delivery bus
250, embodied as a plurality of continuous conductors 230, 232,
234, and two or more tap connection junctions 222. Each of the
inverters 204 are electrically coupled to the power delivery bus
250 to supply power thereto via one of the tap connection junctions
222. The tap connection junctions 222 each include a power bus
connector 214 configured to mate with the power delivery connector
212 of the corresponding inverter 204 to form a mated tap
connection 280 (mated terminals within each mated tap connection
280 in FIG. 5 are indicated by an "x"). Each of the continuous
conductors 230, 232, 234 may be embodied as any type of conductor
capable of conducting electricity including, but not limited to, a
plurality of wires such as braided wire, mono-strand wire, a bus
bar, and/or other conductive structures. As used herein, the term
"continuous conductor" means an electrical conductor having no
in-line separable connection between a first end of the electrical
conductor and a second end of the electrical conductor. For
example, the illustrative continuous conductors 230, 232, 234
extend from a first end 226 of cable assembly 220 to the
remote-most tap connection junction 222 with no interposed
separable connection between the first end 226 and the remote-most
junction 222. As such, AC power received from each inverter 204 is
delivered to the first end 226 (and, in FIG. 4, thence to the AC
junction box 240) by passing through a single separable connector
(i.e., the respective power bus connector 214) between the
respective inverter 204 and the box 240. Conversely, the power bus
150 of the system 100 illustrated in FIGS. 1-3 includes multiple
in-line, mated connectors 116. As such, power delivered from, for
example, the remote-most inverter 104d of the system 100 passes
through multiple connectors 116 between the inverter 104d and the
junction box 120.
It should be appreciated that the particular length of the
continuous conductors 230, 232, 234 and/or the particular number of
tap connection junctions 222 may vary depending on the particular
implementation of the system 200. It should also be appreciated
that each inverter 204 may be "hard mounted" (e.g., via removable
hardware, such as screws) in a position adjacent to its respective
solar panel(s) 202 and that the number and relative physical
positions of inverters 204 may vary considerably among different
system 200 implementations. Use of flexible cables 210 on each
inverter may provide flexibility with respect to the relative
physical placement of inverters in different system configurations
and allow a particular power cable 220 design to accommodate a wide
range of physical system configurations.
Each of the tap connection junctions 222 includes corresponding tap
conductors 230a, 230b, 230c, which are electrically coupled to and
tap off of the continuous conductors 230, 232, 234, respectively.
As such, power is delivered from each inverter 204a-204d to the
power delivery bus 250 (i.e., to continuous conductors 230, 232,
234) via an associated power delivery cable 210, a mated tap
connection 280, and tap conductors 230a, 230b, 230c. An inverter
204a-204d of the kind shown in FIGS. 4 and 5 is referred to herein
as a "tap-connected inverter".
In contrast to the system of FIGS. 1 and 2, in which input and
output connectors 112, 114 on series-connected inverters 104a-104d
form separable mated connections 116 that are serially connected
within the daisy-chained bus 150, the tap-connected inverters 204
in the system 200 of FIGS. 4 and 5 are connected via conductive
connections (i.e., tap conductors 230a, 230b, 230c) that tap off of
the continuous conductors 230, 232, 234. It should be appreciated
that use of taps and continuous conductors, instead of
daisy-chained serial connectors, may result in improved efficiency
because each mated tap connections 280 carry, on average, less
power than mated connectors 116, and hence may have lower losses.
In addition, failure of a mated tap connection 280 in the system
200 may result in loss of power delivery from only the affected
inverter 204, whereas failure of a mated connector 116 in the
system 100 of FIGS. 1 and 2 may result in loss of power delivery
from many, and possibly all, upstream inverters 104. Thus the
system 200 may exhibit improved reliability and availability
compared to the system 100 of FIGS. 1 and 2.
FIGS. 11A through 11C show illustrative embodiments of structures
and methods for forming a tap connection to the power delivery bus
250. It should be appreciated that in each there are no separable
connectors interposed along the length of a continuous conductive
path.
Referring now to FIG. 11A, in one embodiment, the power delivery
bus 250 is embodied as a plurality of insulated path wires 231,
233, 235, which comprise, respectively, continuous conductors 230,
232, 234 (e.g., copper wires); likewise, insulated tap wires 231a,
231b, 231c comprise, respectively, tap conductors 230a, 230b, 230c
(e.g., copper wires). To electrically coupled the tap conductors
230a, 230b, 230c to the continuous conductors 230, 232, 234,
insulation is removed from regions 260a, 260b, 260c of each
insulated path wire 231, 233, 235 to expose a portion of the
respective continuous conductors 230, 232, 234; likewise, an end of
each tap wire 231a, 231b, 231c is stripped of insulation to expose
an end portion of respective tap conductors 230a, 230b, 230c. The
end of each tap conductor is electrically connected to a respective
conductive paths 230, 232, 234 (e.g., by solder) to form a tap
connection (three are shown).
In another embodied as illustrated in FIG. 11b, a tap connection
(only one is shown) is formed by connecting (e.g., by twisting,
soldering) the stripped and uninsulated conductors 230x, 230y, 430a
from three insulated wires 331a, 331b and 431a. Connected in this
way, the conductors 331a and 331b form a portion of continuous
conductive path 230 and conductor 430a forms a tap conductor.
Additionally, in another embodiment as illustrated in FIG. 11c, a
tap connection is formed by crimping together (e.g., by use of a
parallel crimp connector 433) the stripped and insulated conductors
230x, 230y, 430a from three insulated wires 331a, 331b and 431a.
Connected in this way, the conductors 331a and 331b form a portion
of continuous conductive path 230 and conductor 430a forms a tap
conductor. Further, in some embodiments, the insulated wire formed
from wires 331a, 331b is initially cut and stripped to expose
opposing ends of the conductors 230x, 230y. The conductors 230x,
230y and the conductor 430a are subsequently electrically coupled
together (e.g., via a crimped or soldered connection) to form a tap
connection.
In some embodiments, as illustrated in FIG. 12, one or more of the
tap junctions 222 of the cable assembly 220 may be overmolded to
form an overmolded tap junction 500. By overmolding the tap
junction, the resiliency to environmental effects of the cable
assembly 220 is increased. For example, as shown in FIG. 12, the
power bus connector 214 of the overmolded tap junction 500 is inset
or otherwise overmolded to reduce the likelihood of incursion of
debris, water, and/or the like. Any suitable molding process may be
used to form the overmolded tap junction 500.
In the system 200, each tap-connected inverter 104a-104d may
comprise a single cable 210, instead of the pair of cables 108, 110
associated with each series-connected inverter 104a-104d in the
prior art system 100. Furthermore, in normal operation, the power
delivery cables 210 and connectors 212, 214 in the system 200 may
only need to be sized to carry the power that can be delivered by a
single inverter, whereas the cables 108, 110 and connectors 112,
114 in the prior-art system 100 must be sized to carry the full
rated power of the entire array of inverters 104a-104d. For
example, in the prior art system, all of the inverter cables 108,
110 may comprise #12 AWG conductors with equivalently rated
connectors, whereas in some embodiments of the system 200 the
inverter cable 210 may comprise smaller #18AWG conductors with
correspondingly smaller connectors. Thus, a system according to the
present disclosure may be more cost-effective than a prior art
daisy-chained system 100.
In some embodiments, protective circuit elements may be
incorporated in the power delivery system 200 as illustrated in
FIG. 6, which shows a portion of the region of the power delivery
cable 220 that is labeled "A" in FIGS. 4 and 5. As illustrated in
FIG. 6, fuses 246 and surge protectors 254a-254c are installed
within tap connection junction 222. It should be appreciated that
by locating fuses in the tap connection junction, as opposed to
locating fuses in the inverter (e.g., as shown in FIG. 3 for a
prior art system 100), a short circuit in an inverter cable (which
may happen if a cable is, e.g., chewed by a pest, such as a rodent
or squirrel) may affect only a single inverter. Additionally, it
should be appreciated that the magnitude of a fault current that
the cable 210 may have to carry may be limited by the rating of the
fuse, thereby allowing use of smaller conductors in the cable
210.
In other embodiments, protective circuit elements may be
incorporated in the power delivery system 200 as illustrated in
FIGS. 7 and 8. As illustrated in FIG. 7, which shows the portion of
the system 200 that is labeled "A" in FIG. 4, a replaceable series
element 300 comprises connector 314 that connects to power delivery
connector 212 at the end of cable 210, and connector 312 that
connects to power bus connector 214 at tap connection junction 222.
As shown in FIG. 8, circuit protective elements, such as fuses 246
and surge protectors 254a-254c, may be installed within the
replaceable series element 300. Use of the replaceable series
element 300 offers the same benefits discussed above with respect
to FIG. 6 and may also simplify replacement of protective elements
and also simplify the design of the power delivery cable 220 (by
eliminating the need for circuit protective elements, and means for
accessing those elements, if provided, within the cable assembly).
Replaceable series elements may also be configured as extenders to
increase the length of inverter cables 210; such extender cables
may be configured to also include protective elements.
Additionally, in some embodiments, an earth ground may be provided
to an inverter 204 in the power delivery system 200 as illustrated
in FIGS. 9 and 10, each of which shows the portion of the system
200 that is labeled "A" in FIGS. 4 and 5. FIG. 9 shows a portion of
a system 200 comprising a power delivery cable 220 that
incorporates circuit protective elements (not shown in detail in
FIG. 9, but indicated by the element 410) within a tap connection
junction 222; FIG. 10 shows a portion of a system 200 in which a
replaceable series element 300 comprises circuit protective
elements (not shown in detail in FIG. 10, but indicated by the
element 410). In FIGS. 9 and 10, the power delivery cable 220
comprises an earth ground bus conductor 450 and the inverter cable
210 comprises an inverter earth ground conductor 450a that is
connected to a earth grounding point 290 within inverter 204c. In
FIG. 9 the earth ground bus conductor 450 connects to inverter
earth ground conductor 450a via the mated tap connection 280; in
FIG. 10 the earth ground bus conductor 450 connects to inverter
earth ground conductor 450a via the mated tap connection 280 and a
ground conductor 450b in replaceable series element 300.
It is understood that reference to photovoltaic systems is
illustrative and that the present disclosure is equally applicable
to a variety of power delivery system embodiments, e.g., systems
comprising fuel cells or other power generation sources. It should
also be understood although the drawings illustrate power
generating device arrays comprising a particular number of array
elements, the present disclosure may be generally applicable to
arrays including two or more power generating devices.
There is a plurality of advantages of the present disclosure
arising from the various features of the apparatuses, circuits, and
methods described herein. It will be noted that alternative
embodiments of the apparatuses, circuits, and methods of the
present disclosure may not include all of the features described
yet still benefit from at least some of the advantages of such
features. Those of ordinary skill in the art may readily devise
their own implementations of the apparatuses, circuits, and methods
that incorporate one or more of the features of the present
disclosure and fall within the spirit and scope of the present
invention as defined by the appended claims.
* * * * *
References